1. Field of the Invention
This invention relates generally to perpendicular magnetic recording write heads for use in magnetic recording disk drives, and more particularly to a method for making a write head having a trailing shield.
2. Description of the Related Art
Perpendicular magnetic recording, wherein the recorded bits are stored in a perpendicular or out-of-plane orientation in the recording layer, is a promising path toward ultra-high recording densities in magnetic recording hard disk drives. The recording or write head in perpendicular magnetic recording disk drives includes a write pole for directing magnetic field to the recording layer, and one or more return poles for return of magnetic flux from the recording layer. The write head may also include a trailing shield of magnetically permeable material that faces the recording layer and is spaced from the write pole by a nonmagnetic gap. The use of a trailing shield separated from the write pole by a nonmagnetic gap slightly alters the angle of the write field and makes writing more efficient. The portion of the trailing shield that first receives the flux from the write pole must be very thin as measured in the generally perpendicular direction, i.e., perpendicular to the recording layer. This dimension is called the trailing shield's “throat height”. However, it is difficult to reliably fabricate a trailing shield with a precise throat height dimension.
What is needed is a method for making a perpendicular magnetic recording write head that has a trailing shield with a precisely defined throat height.